Explicitly initialize secondary renderers for layout tests.

content/shell/browser/layout_test/layout_test_devtools_frontend.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_SHELL_BROWSER_LAYOUT_TEST_LAYOUT_TEST_DEVTOOLS_FRONTEND_H_
 #define CONTENT_SHELL_BROWSER_LAYOUT_TEST_LAYOUT_TEST_DEVTOOLS_FRONTEND_H_
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "content/shell/browser/shell_devtools_frontend.h"
@@ skipping 23 matching lines @@
   ~LayoutTestDevToolsFrontend() override;
 
   // content::DevToolsAgentHostClient implementation.
   void AgentHostClosed(DevToolsAgentHost* agent_host, bool replaced) override;
 
   // ShellDevToolsFrontend overrides.
   void HandleMessageFromDevToolsFrontend(const std::string& message) override;
 
   // WebContentsObserver implementation.
   void RenderProcessGone(base::TerminationStatus status) override;
+  void RenderFrameCreated(RenderFrameHost* render_frame_host) override;
+  void RenderFrameHostChanged(RenderFrameHost* old_host,
+                              RenderFrameHost* new_host) override;
 
   bool ready_for_test_;
   std::vector<std::pair<int, std::string>> pending_evaluations_;
 
   DISALLOW_COPY_AND_ASSIGN(LayoutTestDevToolsFrontend);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_SHELL_BROWSER_LAYOUT_TEST_LAYOUT_TEST_DEVTOOLS_FRONTEND_H_